


Betrayal

by HavenRyder



Category: Gravity Falls
Genre: Established Relationship, Evil?Dipper, Explicit Language, Explicit Sexual Content, Human!Bill, M/M
Language: English
Status: Completed
Published: 2017-05-20
Updated: 2017-05-20
Packaged: 2018-11-02 10:16:05
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,244
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10942422
Author URL: https://archiveofourown.org/users/HavenRyder/pseuds/HavenRyder
Summary: 5 years after the events of the Gravity Falls series, Weirdmageddon II happens, and this time Dipper is the only one who can stop it. But does he want to?





	Betrayal

The town he had grown to know and love lay in ruins, mangled beyond recognition.

Dipper didn’t bat an eye at the magical flames immolating what was left of the Mystery Shack; the storm of emotions that swirled in this mind felt muted - like he was in shock. A sweep of the area found nothing amiss, so Dipper decided that he was done for the day. Absentmindedly, he cast a levitation spell, flying up to the colossal pyramid that floated in the sky. He walked through the antechamber, each step sending echoes reverberating off the walls and shivers running down his spine. The cavernous room was littered with the citizens of Gravity Falls, their faces frozen in morbid expressions of terror. If Dipper didn’t know better, he would think that he was in a Medusa’s lair. The statue form of Wendy Corduroy guarded the door to the next room. He made the mistake of looking at her, and shuddered involuntarily at the sight of her silent scream.

The next room contained three cages. In the first, Grunkle Stan paced angrily, keeping far away from the electricity-laced steel bars. His lips were moving, no doubt cursing at Dipper, but the magic barrier prevented any sound from coming through. The second cage contained Gideon Gleeful, looking uncharacteristically disheveled in his fancy suit; being forced to dance non-stop had sapped the life out of his eyes. Dipper didn’t dare glance at the last cage, but he knew who it held captive: Mabel, lying on a bed, still in a coma. Pacifica, tending to her with unwavering devotion and waning hope. Dipper hoped that his sister would wake up soon; those few seconds that he thought she was gone forever had been the single worst ordeal of his life. He had barely been able to save her.

With a sigh, Dipper trudged to the bedroom - best not to keep his Demon Lord waiting. 

“So, have you found him?” Bill asked the moment he entered. The demon was sprawled on the bed, casually twirling his yellow-blond curls as he observed the chaos outside the window. 

“No, but I found a good lead. Just another day or two, and I’ll bring him to you.” Dipper assured. “I stopped by the Shack as you said, but there was no sign of tampering with the wards there.”

“I have faith in your abilities. Now come over, pet,” he beckoned. 

Despite how needlessly large the bed was, Dipper settled into Bill’s side, letting his head rest on his chest. Fingers stroked down his side, and he hated himself for how comfortable he found the sensation to be.

“Isn’t it wonderful, Pine Tree? I’ve only had this human form for five days, and all of Gravity Falls is already ours. Once we track down Sixer and break through the barrier, I’ll conquer the world, with you by my side. No more rules for all of eternity! It’s good to see that the past six years of scheming, and teaching you magic, haven’t gone to waste.” He smirked, pointy teeth glinting menacingly.

“All in due time,” Dipper assured, ”but... I can think of a great way to celebrate our success...” he let his voice drop to a low purr, and nibbled at Bill’s neck seductively. It seemed to work, for the dream demon’s eye flashed red momentarily, the pupil narrowing to a slit. 

“What’s gotten into you? Normally, I have to be the one initiating things. Not that I’m complaining,” he pointed out, drawing Dipper into a deep, passionate kiss.

“I don’t know, maybe it’s because we’re in the physical realm; it feels different as compared to when we were in the mindscape.” Dipper explained, “Or maybe you’re just that hot.” He wasn’t lying - Bill had made his human form as close to perfection as possible, with a lithe but strong frame, sharp and refined features, and flawless caramel skin. The closest thing he had to a defect was that he only had one eye, choosing to wear a triangular eyepatch over where his left eye would be. 

Seeing as Bill was still lying beneath him with an amused grin, Dipper decided to take the lead, distracting him with a kiss and tugging at his coat. Curse Bill and his need to be perpetually overdressed; after pulling off the coat, Dipper still had a vest and shirt to deal with, not to mention his trademark bowtie. Dipper groaned in frustration, biting Bill’s lip hard enough to draw blood. Bill bucked under him, then snapped his fingers, instantly removing his clothes. Dipper was treated to a full view of his toned chest and taut muscle, which he longed to kiss and worship. He decided to do just that, trailing kisses down Bill’s body and licking over his abs slowly to tease him, all the while counting the seconds in his head. This time, Bill lasted for a grand total of twenty seconds before growling and flipping their positions, pinning Dipper to the bed. ‘Demons don’t do foreplay,’ he had said once, what now seemed like forever ago. From the lascivious, ravenous look in his eye, Dipper had no doubt that that was the case. A shimmering, cobalt chain of magic materialized, and Bill wrapped it tightly around his wrists, attaching the ends to the headboard. Dipper could instantly feel his magic being restrained; it still flowed in him, but he couldn’t draw it to the surface. It wasn’t like Dipper could actually concentrate enough to cast a spell in the middle of sex, but giving up control like that was insanely hot. 

Next, Bill ripped Dipper’s shirt in half, exposing pale skin marred by the scars he had accumulated over the years. From the cocky grin on Bill’s face, he was well aware of how much that display of strength turned Dipper on. Tossing the shreds of fabric to the side, he dove for Dipper’s neck, sinking his teeth in. He lapped up the crimson blood that flowed out, chasing every last stray droplet that trickled down the boy’s chest. When Bill sucked at the wound, Dipper let out a moan at the combined pain and pleasure. Sure, he was going to hell, but he couldn’t bring himself to care anymore.

After making sure that the marks on his neck had shrunk to pinpoints, Bill captured Dipper’s lips and shoved his tongue into his mouth, forcing the human to taste the metallic tang of his own blood. At the same time, he slipped a hand down Dipper’s pants, grinning when he found no underwear - just the way he preferred it. When Bill pulled back, his hands were tinged with the blue flames, a promise of the depravity to follow. He didn’t keep Dipper waiting for long - a moment later, he straddled Dipper’s face and shoved his cock down his throat. Simultaneously, a magical force spread his legs and coated his entrance with lube. Dipper strained to see what was happening but was distracted by Bill thrusting into his mouth, yanking roughly on his hair. God, he was _long_. Dipper could feel his throat burning, and his lungs felt like they were going to burst. Right when he was convinced that he would pass out from oxygen deprivation, Bill took mercy on him, pulling out and patting his cheek, murmuring, “Good pet.”

He then made a particularly obscene gesture with his fingers, sending a magical construct ramming into Dipper, scraping against his prostate. The strangled cry that he let out seemed to amuse the demon, who repeated the motion. It felt strange, but not unpleasant; smooth, weightless, and… tingly. Dipper hadn’t experienced something like this before, so the sensation when Bill resumed fucking his mouth was overwhelming. Dipper supposed that was what being spit-roasted in a threesome would feel like; not that he would ever find out given how possessive Bill was. His dick was so hard that it was almost painful, and had been utterly neglected so far. Despite his efforts to free his hands to stroke himself yielding no success, Dipper could still feel the tension mounting slowly. So close… Just a couple more thrusts, and he would have his release.

“Not so fast, Sapling,” the magical dildo vanished, leaving Dipper feeling weirdly empty. He whined, which wasn’t easy to do with his mouth stuffed with Bill’s length. “You aren’t allowed to cum without my permission, got it? Let me hear you beg.” Bill ordered.

The few seconds it took for Bill to lube himself up were nearly unbearable. Dipper almost sighed in relief when he felt Bill slide into him, not even bothering to start slow. Both of them liked it rough, something BIll seemed entirely unapologetic about. Apart from Dipper’s gasps and moans, and the slap of skin on skin, the room as silent - while Bill’s expression portrayed the bliss that he was feeling, he usually found making noises to be ‘inelegant’. Either that, or he was waiting for Dipper to say something. 

His cock throbbed, and he cast all dignity to the wind.

“Please...” he breathed, looking at Bill with his best puppy eyes.

“Please who?”

“Please, master...”

“What do you want, Pine Tree?” Bill taunted, slamming into him forcefully.

“Touch me...” Dipper keened. They had shared a sexual relationship for more than a year already, but his face still turned scarlet whenever he was forced to beg.

“My pleasure.” Bill purred. Long fingers wrapped around his shaft, stroking to the rhythm of Bill’s thrusts. “Such a horny little slut, aren’t you?” The words were whispered in his ear, making his toes curl. “I bet you want me to fuck you until you can’t even remember your own name. What an obedient slave. I love you, Dipper, now cum for me.”

The command intensified the heat in his gut; with a startled cry, Dipper let go, feeling waves of pleasure course through his being. Warm cum splattered all over his stomach and Bill’s hand. The demon licked his fingers clean with a smirk, but didn’t change his pace. Finally, after a few more moments of torturous overstimulation, Dipper felt Bill spill into him, before pulling out with a satisfied sigh.

With a snap of his fingers, the chains vanished, allowing Dipper to summon a cloth and wipe himself down, before throwing it to Bill, who cleaned himself before lying down beside Dipper. The protective way that Bill embraced him and pecked his lips almost crumbled Dipper’s resolve. He savored every last second he had, knowing that he only had a short window of time when Bill’s guard would be down as a result of his post-orgasmic bliss. It was ironic considering what he was going to do next, but he still found himself healing the scratches he had left on Bill’s back.

Dipper was relieved to find that his magic surged readily to his fingertips when summoned. He began the spell, murmuring the Latin words under his breath. It seemed to be working - he could feel the energy draining out of him and forming a circle of runes around Bill. The demon noticed instantly, of course, but it was too late.

“What are you doing?” Bill shrieked, voice trembling with rage, “Let me go right now, or I swear I’ll punish you for all of eternity when I break free.”

Ignoring his threats, Dipper continued reciting. By then, the words seemed to spill out of him, as if the spell was clamoring to be completed. Only when uttered the last line did he dare to glance at Bill. The demon’s eye was no longer glowing red, and he looked resigned.

“You know I could kill you physically and break the spell, right?”

“You won’t,” Dipper didn’t even try to hide the tears streaming down his face. He scooted backward, hugging his legs tightly. “I’m so sorry Bill.. I...”

“Why?” Bill looked genuinely confused, “What did I ever do to make you betray me?”

“You betrayed me first. You promised that no harm would come to those whom I love. Mabel nearly died when you deflected her attack back at her!” Dipper exclaimed.

“It was an accident, okay? She’s going to wake up soon, anyway.”

“It’s not just that. You think Grunkle Ford will just tell you how to escape from Gravity Falls? I’m not letting you torture him again. The truth is, I’ve already hurt all of them. By making a deal with you, by letting you destroy this town. They may never forgive me… You’ll never forgive me… But I know I’m doing the right thing.”

Bill chose not to reply to that, instead asking, “Did you ever love me?”

“I love you, Bill. I always have. Fuck, this is the hardest thing I’ve ever done. The mistake I made was believing you could ever be human; you don’t even understand the concept of pain, so how are you supposed to feel empathy? I should never have let it come this far.” Dipper choked.

A single tear trickled slowly down Bill's face. “I think I know what pain is now,” he answered. The demon looked so different from how he was earlier - gone was the dominance, the smugness, the hint of mania. That sight was one that would haunt Dipper for the rest of his life, for sure.

“For what it’s worth, I’m sorry.” Dipper whispered, collapsing on the bed and closing his eyes. 

He felt the last of the magic leave him; the spell was complete. It was all over.

**Author's Note:**

> I'm new to this fandom, so be go easy on me, please? That being said, all comments are greatly appreciated! ^^


End file.
